The present invention relates to a vehicular headlamp. More particularly, the present invention relates to a vehicular headlamp having improved aiming adjustment of two reflectors in a vehicular headlamp including first and second reflectors, the reflectors each being tiltable by turning an aiming screw of a corresponding aiming mechanism that supports the corresponding reflector in an adjustably tiltable manner relative to the lamp body.
One type of vehicular headlamp has two reflectors arranged so as to be separately tiltable within a single lamp-fixture chamber defined by a lamp body having a recessed portion at its front and a lens covering the front opening of the lamp body. Such a headlamp may be used, for example, in a so-called four-lamp headlamp system having a main-beam reflector and a sub-beam reflector arranged on each of the right and left front portions of the automobile.
In such a headlamp, the two reflectors are supported in a tiltable manner on the lamp body via respective aiming mechanisms. Such an aiming mechanism is generally composed of a single pivot fulcrum portion and two spacing adjustment portions. Each spacing adjustment portion is composed of an aiming screw rotatably supported on the lamp body and a nut member into which the aiming screw is fitted. The nut member is attached to the reflector. By turning the aiming screw, a threaded shaft portion of the aiming screw is screwed into or out of the nut member, depending on the direction of rotation, so that the spacing between the portion of the lamp body supporting the aiming screw and the portion of the reflector to which the nut member is attached is adjusted. Accordingly, turning the aiming screw in one spacing adjustment portion tilts the reflector about the line connecting the pivot fulcrum portion and another spacing adjustment portion.
Reflectors are pivotable by the aiming mechanisms as described above for the purpose of enabling adjustment of the radiation axes of the beams from the respective reflectors. If the radiation axes of the beams have not been properly adjusted, the beams of the vehicular headlamp cannot illuminate required portions of the road ahead, or glare may be created for drivers of oncoming vehicles and pedestrians.
Therefore, proper adjustment of the radiation axes of the beams, that is, aiming adjustment, is required for the vehicular headlamp before shipping from the factory, and such aiming adjustment is also required as appropriate after use.
It is troublesome to conduct such an aiming adjustment of the two reflectors separately. In other words, the main beam and the sub beam are capable of producing the best running beams when the radiation axes of the two beams are properly combined and aligned. Therefore, it is quite troublesome and difficult to maintain the desired alignment between the radiation axes while tiltably adjusting the two reflectors separately.
Even if the radiation axes of the two reflectors are properly adjusted prior to shipment from the factory, it is difficult for a general user or mechanic without special instruments to conduct proper adjustment.
Therefore, attempts have been made to provide an aiming mechanism where the two aiming screws of two aiming mechanisms are turned simultaneously in order to adjust the tilt angle of the two reflectors simultaneously. According to one such attempt, the two aiming screws are linked to each other via a plurality of gears so that the rotation of one of the aiming screws causes turning of the other aiming screw via the plurality of gears.
Turning two aiming screws in conjunction with each other facilitates maintaining the proper alignment of the radiation axes of the two reflectors. However, accommodating the gear train within the lamp chamber may be difficult depending on the positional relation between the aiming screws to be operated in conjunction with each other.
Moreover, operating the two aiming screws in conjunction with each other via the gear train increases the number of parts, and also complicates the overall structure.
It is an object of the present invention to facilitate the aiming adjustment of two reflectors and enable the aiming adjustment to be conducted regardless of the positional relation between aiming screws operating in conjunction with each other.
In order to solve the aforementioned problems, the vehicular headlamp of the present invention includes a belt mechanism for allowing a first aiming screw, for adjusting the tilt angle of the first reflector, and a second aiming screw, for adjusting the tilt angle of the second reflector, to be turned in conjunction with each other.
In the vehicular headlamp of the present invention, turning only one of the aiming screws effects turning of the other aiming screw as well. This facilitates aiming adjustment and allows the aiming adjustment to be conducted without disturbing the alignment of the radiation axes of the two reflectors that have been matched in advance.
The aiming screw indirectly turned via the belt mechanism may be located at a position which is less accessible for direct operation from the outside, thereby improving design flexibility.
Moreover, since the two aiming screws operate in conjunction with each other due to the belt mechanism, it is possible to turn them in conjunction with each other regardless of the positional relation therebetween.